Moving stairway



7 Sheets-Sheet l INVENTOR ATTNEY June 27, 1939. s. G. MARGLES MOVINGSTAIRWAY Filed May 20, 1957 5M GMQW 2 @wawmMw June 27, 1939. s MARGLES2,163,693

MOVING STAIRWAY Filed May 20, 1937 '7 Sheets-Sheet 2 TORNEY June 27,1939. 5. ca. MARGLES MOVING STAIRWAY Filed May 20, 1937 '7 Sheets-Sheet3 M 7 G INVENTOE ATTORN Y June 27, 1939. s. ca. MARGLES MOVING STAIRWAYF gled May 20, 1957 '7 Shets-Sheet 4 SMW 4 INVENTOR ATTORNEY June 27,1939. 5 MARGLES 2,163,693

MOVING STAIRWAY Filed May 20, 1937 7 Sheets-Sheet 6 4 INVEmOR Q BYATTORNEY June 27, 1939. s. G. MARGLES MOVING STAIRWAY Filed May 20, 1937'7 Sheets-Sheet 7 SM (124 444 i INVENTOR ATTORNEY Patented June 27, 1939I UNITED STATES PATENT OFFICE 2,163,693 MOVING STAIRWAY Samuel GustaveMargles, Brooklyn, N. Y., as-

signor to Otis Elevator Company, New York, N. Y., a corporation of NewJersey Application May 20, 1937, Serial No. 143,652

9 Claims. (01. 19816) The invention relates to moving stairways. rollersof the running gear chains with the teeth Moving stairways comprise anendless series of the sprocket wheels. of steps which are moved from onelanding to Features and advantages of the invention will another for thepurpose of conveying passengers. be apparent from the followingdescription and The steps are connected together by means of appendedclaims. 5

sprocket chain, known as running gear chain. In the drawings:- It hasbeen the practice for a considerable num- Figure 1 is a diagrammaticrepresentation in ber of years to provide a running gear chain on sideelevation of a moving stairway showing one each side of the stairway andto drive these arrangement for maintaining the wheels of the chains bymeans of sprocket wheels at the upper step in continuous engagement withtheir tracks; 10 end of the stairway. The steps are supported on Figure2 is an enlarged rear view of one of the each side by wheels which runon tracks. steps of the moving stairway of Figure 1; Sprocket wheels maybe provided at the lower Figure 3 is a view taken along the line 33 ofend of the stairway for the chains to carry the Figure 2; ,7

steps around the bend or the steps may be sup- Figure 4 is adiagrammatic representation in 15 ported in passing around the bendsolely by side elevation of a moving stairway showing ancurved tracksfor the supporting wheels of the other arrangement for maintaining thewheels of steps. It is desirable that moving stairways opthe step incontinuous engagement with their erate as smoothly and noiselessly aspossible. tracks;

Many improvements have been made with the Figure 5 is an enlarged rearview of one of the 20 view of aiding in accomplishing this purpose.steps of the moving stairway of Figure 4; One of the problems has beenthe bringing of the Figure 6 is a view taken along the line 66 of stepssmoothly and noiselessly around the bends Figure 5; at the ends of thestairway. Figure '7 is a diagrammatic representation in The object ofthe invention is to eliminate noise side elevation of a moving stairwayshowing an- 5 incident to the transfer of the steps from one run otherarrangement for maintaining the wheels to the other at the ends of thestairway. in continuous engagement with their tracks;

The invention involves the provision of a plu- Figure 8 is an enlargedrear view of one ofthe rality of wheels for each step and a track systemsteps of the moving stairway of Figure 7; having a continuous track foreach wheel, and Figure 9 is a view taken along the line 9-9 of 30maintaining all of these wheels at all points in Figure 8; the travel ofthe step in contact with their tracks. Figure 10 is an enlargedfragmental detail Several arrangements will be described as illusshowingone arrangement of employing sound trative of modes of carrying out theinvention. In deadening material to deaden the noise of coneacharrangement described, each step is provided tact of chain rollers witha sprocket wheel; 35 on each side with two wheels, one of which isFigure 11 is an enlarged fragmental detail associated with the runninggear chain. Conshowing another arrangement of employing tinuous tracksare provided for these wheels. sound deadening material to deaden thenoise of Each step is provided with one additional wheel contact ofchain rollers with a sprocket wheel;

common to the two sides of the stairway or with and 40 two additionalwheels, one for each side of the Figure 12 is a detail in section taken.along the stairway. A continuous track is provided for each line l2i2 ofFigure 11. additional wheel. Each additional wheel is In each of thearrangements illustrated, the

mounted for relative movement with respect to stairway comprises anendless series of steps ill the other wheels, a resilient connectionbeing driven at the upper end of the stairway by means 45 providedbetween the additional wheel and the of sprocket wheels through runninggear chains, step for exerting a force between the additional a sprocketwheel and chain being arranged on wheel and the other wheels which actsto maineach side of the stairway. A sprocket wheel I l tain all thewheels in engagement with their and running gear chain i2 areillustrated for one tracks at all times. side of the stairway. Thesprocket wheels are 60 As another aspect of obtaining quiet operationmounted on and driven by the main drive shaft of the stairway as thesteps pass around an end .I5, driven in turn by driving mechanism (notof the stairway at which the chains mesh with shown). 4 sprocket wheels,sound deadening material is Referring to Figures 1, 2 and 3, each stepcomutilized to deaden the sound of contact of the prises a step frame I6upon which the tread I1 86 is mounted. The frame is mounted on elongatedbrackets I8, one on each side of the stairway, extending underneath theframe. A chain wheel 28 and a trailer wheel 23 is provided for each stepon each side thereof. The chain wheels are mounted on an axle 2|extending across the stairway through opposite chain links in therunning gear chains, the chain wheels being outside the links of thechains. The axle is supported by bearings IS in the brackets. Each ofthe trailer wheels 23 for the step is mounted on a stub axle 24supported by the other end of the step bracket 1.

A track 22 is provided on each side of the stairway for the chainwheels. A track 25 is also provided on each side of the stairway for thetrailer wheels. Each of these tracks comprises an upper run portion anda return run portion joined at the ends by curved end portions to form acontinuous track. These tracks are positioned and shaped to give theproper position to the steps at the various points in their travel.Mechanism is provided for maintaining the wheels in continuous contactwith their tracks, without which the wheels, in passing around the bendfrom the upper run to the return run at an end of the stairway, wouldleave their tracks and would remain off the tracks until the transitionfrom the return run to the upper run is made at the other end of thestairway.

In the form illustrated in the figures being described, this mechanismcomprises for each step an additional wheel 26, a track 21 for thiswheel and a spring 28 acting oppositely on the additional wheel and thechain and trailer wheels to exert the forces maintaining these Wheels ontheir respective tracks. The track 21 for the additional Wheel isarranged intermediate the sides of the stairway and is shaped tomaintain the same relative positions of the wheels regardless of wherethe step may be in its travel. The additional wheel runs on the insideof its track as distinguished from the chain and trailer wheels, whichrun on the outside of their tracks.

The additional wheel 26 is supported on a stub shaft 29 carried by anarm 30 of lever 3|. This arm forms an extension at right angles from aU- shaped portion 32 which is pivotally mounted on axle 2| betweenbrackets l8. A channel shaped member 33 extends between the brackets andis apertured at 34 to slidably receive a stud 35. This stud is securedto the yoke 36 of the U-shaped portion 32 by lock nut 31. The spring 28is arranged on the stud and is held in a state of compression betweenthe channel member 33 and a washer 38 on the outer end of the stud byadjustable lock nuts 40. Lever 3| is constructed so as to locate wheel26 intermediate the chain and trailer wheels as viewed in Figure 3.Likewise the channel shaped member 33 is intermediate these wheels. Asspring 28 is in a state of compression, it acts through washer 38, nuts40 and stud 35 to exert a force to maintain wheel 26 in engagement withits track surface. In so doing the spring acts through channel member 33and brackets |8 to exert a force to maintain the chain and tralierwheels on their respective track surfaces. The channel member 33 beingintermediate these wheels, causes this force to be exerted equally onthe chain and trailer wheels. With this construction, the wheels aremaintained in rolling engagement with their respective track surfacesregardless of the position of the step in its travel, as may be seenfrom Figure 1, in which the steps are illustrated at various points ofstep travel. Thus any noise incident to the wheels passing around thebends at the, ends of the stairway is eliminated.

It is preferred not to provide rollers in the running gear chain wherethe chain wheel axles extend through the chain. This obviates any noiseincident to meshing of chain wheel rollers with the sprocket wheelswhich might otherwise occur, particularly after Wear of the chain wheelshas taken place. Also, a certain amount of clearance is provided betweenlock nut 31 and channel member 33. This insures spring 28 beingeffective to maintain the wheels on their respective tracks after wearof the wheels has taken place.

Referring now to the arrangement shown in Figures 4, 5 and 6, the stepframe is mounted on brackets 45, one on each side of the stairway. Eachof these brackets is formed with a cross member 49 and an arm 5|,somewhat in the nature of a T except that the arm is at an acute angleto the cross member in the direction of movement of the stairway whileascending. A wheel 46 is provided for each step on each side thereof.These wheels are mounted on an axle 41 extending across the stairway,preferably midway of the step tread. This axle extends through oppositechain links in the running gear chains, the wheels being outside thelinks of the chain. The axle is supported by bearings 44 in the crossmembers 49 of the brackets. The Wheels 46, being associated with thechains, will be termed chain wheels.

In addition to the chain wheels, each step is provided on each sidethereof with two additional wheels. One of these wheels, designated 48,is

mounted on a stub axle 50 supported by the end of arm 5| of bracket 45.The other wheel, designated 52, is mounted on a stub axle 53 supportedby the end of a lever 54 pivotally mounted on axle 41 between bracket 45and the running gear chain. The lever 54 is arranged at an angle to arm5| of bracket 45 as indicated in Figure 6.

A track 55 is provided on each side of the stairway for the chainwheels. A track 56 is also provided on each side of the stairway for thebracket wheels 48. Likewise, a track 51 is provided on each side of thestairway for wheels 52. Each of these tracks comprises an upper runportion and a return run portion joined at the ends by curved endportions to form a continuous track. The chain wheels run on the outsideof their tracks, whereas wheels 48 and 52 run on the inside of theirtracks. The tracks are positioned and shaped to give the proper positionto the steps at the various points in their travel. In the constructionillustrated, the track surface for wheels 52 on each side of thestairway may be aligned with that for wheels 48 for the inclined portionof the upper run of the stairway, as illustrated in Figure 4. Ifdesired, the construction may be such that for this portion of the run acommon widened track may be used on each side of the stairway.

The wheels of each step are maintained on their respective tracksurfaces by means of springs 66, one on each side of the stairway. Theconstruction for each side of the stairway is the same. The spring is acompression spring and is positioned between oppositely disposed lugs 6|and 62 provided on lever 54 and arm. 5| respectively. The spring isarranged on a stud 63 threaded into an aperture in lug 6| and securedthereto by a lock nut 64. The stud slidably extends through an aperture65 provided in the other lug 62. Lock nuts 66 on the outer end of thestud limits the amount of spread of the wheels.

As spring 60 is in a state of compression, it

' acts through the lugs to exert a force to maintain wheels 48 and 52 inengagement with their respective track surfaces. In so doing, it spreadsthe lever 54 and arm 5| of the bracket apart to draw the chain wheel 46into engagement with its track surface. Thus, with this constructionalso, the wheels of the step are maintained in rolling engagement withtheir respective track surfaces, regardless of the position of the stepin its travel, as may be seen from Figure 4, so that any noise incidentto the wheels passing around the bends at the ends of the stairway iseliminated.

In this arrangement also it is preferred to omit the rollers in therunning gear chain where chain wheel axles extend through the chain, toobviate noise incident to the meshing of chain wheel rollers with thesprocket wheels. Also, a certain amount of clearance is provided betweenlock nuts 66 and lugs 62 to insure springs '60 being effective tomaintain the wheels on their tracks after wear of the wheels has takenplace. It is preferred to employ springs that are strong enough tomaintain the wheels on their track surfaces when the weight on the stepis concentrated on the right hand side of the tread as viewed in Figure6.

Referring now to the arrangement shown in Figures 7, 8 and 9, the stepframe is mounted on brackets 10, one on each side of the stairway. Eachof these brackets has a portion 61 extending beneath the step frame andan angular portion depending therefrom and having two arms 68 and 69,thereby forming a triangle, arm 69 being at an acute angle to portion 61in the direction of movement of the step while descending. A wheel H isprovided for each step on each side thereof. These wheels are mounted onan axle 12 extending across the stairway, preferably midway of the steptread. This axle extends through opposite chain links in the runninggear chains and the wheels are outside the links of the chain. The axleis supported by bearings 18 in the brackets at the point of joinder ofarms 68 and 69. These wheels, being associated with the chains, willalso be termed chain wheels.

In addition to the chain wheels, each step is provided on each sidethereof with two additional wheels. One of these wheels, designated 13,is mounted on a stub shaft 14 supported by the upper end of the bracketas viewed in Figure 9. The other wheel, designated 15, is mounted on astub shaft 16 supported by a lever 11 pivotally mounted on axle 12between bracket 10 and the running gear chain. Lever 11 is at an angleto arm 69 of the bracket. With this arrangement, the wheels 13 and 15are outside the chain and chain wheels, whereas in the arrangement ofFigures 4, 5 and 6 the wheels 48 and 52 are inside the chain and chainwheels.

A track for the chain wheels, a track 8| for wheels 13 and a track 82for wheels I5 are provided on each side of the stairway. Each of thesetracks comprises an upper run portion and a return run portion joined atthe ends by curved end portions to form a continuous track. The chainwheels run on the outside of their tracks whereas wheels 13 and 15 runon the inside of their tracks. The tracks are positioned and shaped togive the proper position to the steps at the various points in theirtravel. As in the arrangement of Figures 4, 5 and 6, the track surfacefor wheel 13 on each side of the stairway may be aligned with that forwheel 15 for the inclined portion of the upper run of the stairway. asillustrated in Figure 7. If desired, the construction may be such thatfor this portion of i the run a common widened track may be used on eachside of the stairway.

The wheels of each step are maintained on their respective tracksurfaces by means of springs 85, one on each side of the stairway. Theconstruction for each side of the stairway is the same. The spring is atension spring and is secured at one end to a pin 86 secured to bracket10 near stub shaft 14 and at the other end to the lever 11 near the stubshaft Ii. As the spring is in a state of tension, it acts to exert aforce to maintain wheels 15 and 13 on their respective track surfaces.In so doing, it pulls lever 11 and arm 69 of the bracket toward eachother to push the chain wheel 1| into engagement with its track surface.Thus, with this construction also, the wheels of the step are maintainedin rolling engagement with their respective track surfaces regardless ofthe position of the step in its travel, as may be seen from Figure 7, sothat any noise incident to the wheels passing around the bends at theends of the stairway is eliminated.

In this arrangement also it is preferred to omit the rollers in therunning gear chain where the chain wheel axles extend through the chain,to obviate noise incident to the meshing of the chain wheel rollers withthe sprocket wheels.-

Inasmuch as springs 85 are tension springs, they remain effective tomaintain the wheels on their respective track surfaces after wear of thewheels has taken place. It is preferred to employ springs that arestrong enough to maintain the wheels on their track surfaces when theweight on the step tread is concentrated on the right hand side of thetread as viewed in Figure 9.

In the arrangement of Figures 1, 2 and 3, a pair of wheels for eachstep, one on each side of the-stairway, each mounted on a separate leverand having a separate spring for acting between it and the chain andtrailer wheels on that side of the stairway, may be employed in lieu ofwheel 26, lever 3| and spring 28, common to both sides of the stairway.Likewise, one wheel, lever and spring, common to both sides of thestairway, may be employed for each step instead of the wheel 52, lever54 and spring 60 of Figures 4, 5 and 6 or'the wheel 15, lever 11 andspring 85 of Figures 7, 8 and 9 for each side of the step. It is to beunderstood that other arrangements may be provided to cause all of thewheels of the step to be maintained on their tracks at all points intheir travel. Also, the invention may be applied to other forms ofmoving stairway construction, that shown being chosen for convenien'ceof illustration. In other words, the con struction of the track systemand the mechanism for maintaining the wheels of the step on their tracksurfaces may be arranged to suit the particular installation. Not onlydoes the maintaining of all the wheels of the step on their tracksimprove the operation of the stairway from the standpoint of quietnessin operation but also minimizes wear of the wheels.

For the purpose of further improving the quietness of operation as thesteps pass around an end of the stairway at which the chains mesh withsprocket wheels, sound deadening material may be employed to deaden thesound of contact as meshing of the chain rollers with the sprocket;

wheels takes place. Arrangements of this character are disclosed inFigures 10, 11 and 12. In the arrangement of Figure 10, the sides andbottom of the grooves between the teeth of the sprocket wheel are facedwith sound deadening material, whereas in the arrangement of Figures 11and 12 the chain rollers are provided with tires of sound deadeningmaterial. Various sound deadening materials may be employed for thispurpose. Rubber has been illustrated. The rubber is preferably securedto the sprocket wheel or chain rollers by vulcanizing. Synthetic rubberis particularly suitable owing to the fact that the wheels of the stepare subject to oil. With either arrangement, as the chain runs on to thesprocket wheels, the chain rollers, in meshing with the sprocket wheel,are seated silently in the grooves between the teeth of the sprocketwheel so that any noise incident to the meshing of these rollers withthe sprocket wheel is eliminated. In each of these figures, the rollersof the chain where the chain wheel axles extend through the chain havebeen omitted. It is to be understood, however, that rollers may beprovided at this point if desired, particularly where sound deadeningmaterial is employed. If desired, sound deadening material may be usedto deaden the sound of contact of the chain rollers with the sprocketwheels in moving stairways of constructions other than those shown inFigures 1 to 9 inclusive.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A moving stairway comprising; a series of steps; a step frame foreach step; running gear chain; a chain wheel for each step mounted onthe step frame for that step and connected to said chain; an additionalwheel for each step mounted on the step frame for that step; a thirdwheel for each step; a continuous track for each of said wheels of thesteps; means for each step for mounting said third wheel for that stepfor relative movement with respect to said step frame for that step; andresilient means for each step acting between said step frame and saidmounting means for said third wheel for that step to exert opposingforces thereon, with said mounting means for the third wheel positioningthat wheel with respect to said chain wheel and additional wheel forthat step to cause one component of said force exerted by the resilientmeans on the step frame to be applied to the chain wheel in a directiontoward its track and another component thereof to be applied to theadditiona wheel in a direction toward its track, thereby causing thechain wheel and additional wheels to be maintained on their respectivetracks at all points of step travel.

2. A moving stairway comprising; a series of steps; a step frame foreach step; running gear chain; a chain wheel for each step mounted onthe step frame for that step and connected to said chain; an additionalwheel for each step mounted on the step frame for that step; a thirdwheel for each step; a continuous track for each of said wheels of thesteps, said chain wheel for each step rolling on the outersurface of itstrack and at least one of the other wheels for that step rolling on theinner surface of its track; a spring for each step; and means for eachstep for mounting said third wheel for that step for relative movementwith respect to said step frame for that step and for connecting one endof said spring for that step to said step frame and the other end tosaid mounting means for the third wheel with the relationship of thethird wheel with respect to said chain wheel and additional wheel forthat step such as to cause the spring to exert force on the chain wheelto maintain it on its track, to exert force on the additional wheel tomaintain it on its track, and to exert force on the third wheel tomaintain it on its track, regardless of the position of the step in itstravel.

3. A moving stairway comprising; a series of steps; a step frame foreach step; running gear chain; a chain wheel for each step; an axle foreach chain wheel mounted on the step frame for that step and connectedto said chain; an additional wheel for each step; an axle for eachadditional wheel mounted on the step frame for that step; a third wheelfor each step; a continuous track for each of said wheels,'said chainwheel for each step rolling on the outer surface of its track and atleast one of the other wheels for that step rolling on the inner surfaceof its track; a lever for each step pivotally mounted on the chain wheelaxle for that step; a spring for each step connected at one end to thestep frame of the step and at the other end to said lever for that stepbiasing the frame and lever for movement in opposite directions aboutthe chain wheel axle; and means mounting said third wheel for each stepon the lever for that step in such relationship with respect to saidchain wheel and additional wheel for that step to cause forces exertedby the spring for that step to act to maintain the chain wheel, theadditional wheel and the third wheel on their respective tracks,regardless of the position of the step in its travel.

4. A moving stairway comprising; a series of steps; running gear chain;a chain wheel for each step; a trailer wheel for each step; an axle foreach of said wheels for each step; means for mounting said axles on saidsteps, the axle for the chain wheels for each step passing through linksof said chain, thereby connecting said steps together; an additionalwheel for each step; a lever for each step pivotally supported by thechain wheel axle for that step; an axle for each additional wheelmounted on the lever for the step for which the wheel is provided; acontinuous track for each of said wheels of each step for guiding themduring movement of the step; and a compression spring for each stepacting between said lever and said mounting means for the axles of thechain and trailer wheels for that step at a point intermediate suchaxles to exert forces to maintain 'all of said wheels for that step ontheir respective tracks, regardless of the position .of the step in itstravel.

5. A moving stairway comprising; a series of steps; a chain wheel foreach step; a second wheel for each step; means for mounting each chainwheel on the step for which it is provided underneath the step andmidway between the front and back of the tread thereof; means mountingeach second wheel on the step for which it is provided so that when thestep is on the incline of the upper run of the stairway the wheel isbelow and toward the top of the stairway from the chain wheel for thatstep; a lever for each step pivotally secured thereto; an additionalwheel for each step mounted on the end of said lever for that step, saidlever extending below said step when the step is on the incline of theupper run in such direction that the wheel is toward the bottom of thestairway from the second wheel for that step; a continuous track foreach of said wheels of each step for guiding them during movement of thestep; and a compression spring for each step acting between the end ofsaid lever and said mounting means for the second wheel for that step tomaintain said second and additional wheels for that step on theirrespective tracks and in so doing to pull said chain wheel for that steponto its track.

6. A moving stairway comprising; a series of steps; a chain wheel for.each step; a second wheel for each step; means for mounting each chainwheel on the step for which it is provided underneath the step andmidway between the front and back of the tread thereof; means mountingeach second wheel on the step for which it is provided so that when thestep is on the incline of the upper run of the stairway the wheel isbelow and toward the top of the stairway from the chain wheel for thatstep; a lever for each step pivotally secured thereto; an

' additional wheel for each step mounted on the end of said lever forthat step, said lever extending below said step when the step is on theincline of the upper run in such direction that the wheel is toward thebottom of the stairway from the second wheelfor that step; a continuoustrack for each of said wheels of each step for guiding them duringmovement of the step, the chain wheels rolling on the outside surface oftheir track while the second and additional wheels roll on the insidesurfaces of their respective tracks; and a compression spring for eachstep acting between the end of said lever and said mounting means forthe second wheel for that step to spread said second and additionalwheels for that step apart and thus maintain them on their respectivetracks and in so doing to pull said chain wheel for that step towardsaid second and additional wheels and thus maintain it on its track.

7. A moving stairway comprising; a series of steps; a chain wheel foreach step; a second wheel for each step; means for each step formounting said chain wheel and second wheel for that step on the step sothat when the step is on the incline of the upper run of the stairwaythe second wheel is above and toward the top of the stairway from thechain wheel; an additional wheel for each step; means for each step formounting said additional wheel for that step for relative movement withrespect to the other wheels of that step and so that when the step is onthe incline of the upper run the additional wheel is above the chainwheel and toward the bottom of the stairway from both the chain wheeland second wheel for that step; a continuous track for each of saidwheels of each step for guiding them during movement of the step, thechain wheel rolling on the outside surface of their track while thesecond and additional wheels roll on the inside surfaces of theirrespective tracks; and a tension spring for each step acting betweensaid mounting means for the additional wheel and said mounting means forthe chain and second wheels for that step to pull said second andadditional wheels for that step toward each other and thus maintain themon their respective tracks and in so doing to push said chain wheel forthat step away from said second and additional wheels and thus maintainit on its track.

8. A moving stairway comprising; a series of steps; a sprocket wheel atan end of the stairway; running gear chain driven by said sprocketwheel; a plurality of wheels for each step, one of which is a chainwheel; an axle for each of said wheels for each step; means for mountingsaid axles on said steps, the axles for said chain wheels passingthrough certain links of said chain in place of chain pins, therebyconnecting said steps together; track for each of said wheels of eachstep for guiding themduring movement of the step, each track comprisingan upper run and a return run joined at their ends by curved end tracksto form a continuous track; and a spring for each step acting throughsaid mounting means for said axles for said wheels of that step to exertforces to maintain all of said wheels for that step on their respectivetracks, the running gear chain being provided with rollers betweenthelinks on the pins joining the links but not on the axles for said chainwheels, the chain being supported at these points when in mesh with thesprocket wheel by said chain wheels rolling on the curved end portion oftheir track at the end of the stairway at which said sprocket wheel islocated.

9. A moving stairway comprising; a series of steps; a sprocket wheelatan end of the stainway; running gear chain driven by said sprocketwheel; a plurality of wheels for each step; an axle for each of saidwheels for each step; means for mounting said axles on said steps, theaxle for a certain one of said wheels for each step passing throughcertain links of said chain in place of a chain pin, thereby connectingsaid steps together; track for each of said wheels of each step forguiding them during movement of the step, each track comprising an upperrun and a return run joined at their ends by curved end tracks; andresilient means for each step acting through said mounting means forsaid axles for said wheels of that step to maintain all of said wheelsfor that step on their respective tracks, the running gear chain beingprovided with rollers on the pins joining the links but not on the axlesfor said certain wheels, the chain being supported at these points whenin mesh with the sprocket wheel by said certain wheels rolling on thecurved end portion of their track at the end of the stairway at whichsaid sprocket wheel is located.

SAMUEL GUSTAVE MARGLES.

